"Omg! My mouth is on fire, but this curry is sooo good!"
The kanji and the word are exactly the same. That means they share meanings as well. That being said, this can also mean difficult or painful as well. I guess if you're in a spicy situation it's going to be a difficult one.
Depending on the context, the reading for this word could be からい or つらい. The からい reading is the spicy one, you can remember that because that spicy feeling comes from (から) your mouth. The つらい reading is the difficult or painful one. You can remember this because two Ras (つら) are way more difficult to deal with than one Ra.